Apparatus for cracking and burning hydrocarbons

ABSTRACT

A device for cracking and burning hydrocarbons, comprising a chamber for mixing fuel gas and combustion-supporting gas, a baffle member in the outlet orifice of the chamber, a conduit extending through the central zone of the baffle member and terminating on the side opposite to the mixing chamber and being supplied with hydrocarbons, and means for supplying oxygen or superoxygenated air to the periphery of the baffle member.

United States Patent Ivernel APPARATUS FOR CRACKING AND BURNING HYDROCARBONS Inventor: Alix lvernel, Paris, France Assignee: LAir Liquide Societe, Anonyme Pour LEtude et Exploitation des Procedes Georges Claude, Paris, France Filed: June 1, 1970 Appl. No; 42,259

US. CL ..23/259.5, 23/277 R, 23/2094, 239/421, 239/561, 239/591, 431/8, 431/187,

' 431/l7l,431/354, 260/679 R Int. Cl. ..B0lj l/00, C09c l/48 Field of Search ..23/259.5, 209.4, 277; 239/422, 239/561, 591; 431/8, 187, 171, 354; 260/679 Mar. 14, 1972 [56] References Cited UNITED STATES PATENTS 2,862,545 12/1958 Snow et al. ..239/422 3,060,003 10/ 1962 Williams ..23/209 4 3,453,084 7/1969 lverneletal.

Primary Examiner.lames l-l. Tayman, Jr. Attomey-Young and Thompson [57] ABSTRACT A device for cracking and burning hydrocarbons, comprising a chamber for mixing fuel gas and combustion-supporting gas,

a baffle member in the outlet orifice of the chamber, a conduit extending through the central zone of the baffle member and terminating on the side opposite to the mixing chamber and being supplied with hydrocarbons, and means for supplying oxygen or superoxygenated air to the periphery of the baffle member.

5Claims,2DrawingFigures PATENTEUMR 14 I972 SHEET 2 [1F 2 APPARATUS FOR CRACKING AND BURNING I-IYDROCARBONS The present invention relates to a device for cracking and burning hydrocarbons, comprising: means for supplying fuel gas and combustion-supporting gas to said device; a mixing chamber for said gases, said chamber having an opening for the outlet of the mixture; a baffle member fixed to the mixing chamber and disposed outside said chamber in said opening of the chamber; a conduit passing through said baffle member and terminating centrally on the side opposite to the mixing chamber; means for supplying hydrocarbons to said conduit, said mixture passing round the baffle member after passing out of the opening, and then returning toward to the bafile member in the opposite direction to the flow of hydrocarbons passing out of said conduit.

Devices of this kind are known, for example from U.S. Pat. No. 3,453,084. They constitute burners and the cracking of the hydrocarbons may be utilized with advantage, either to increase the luminosity of the flame and therefore the transmission by radiation of the heat which it produces, or to produce carbon black by an abrupt cooling of the combustion mixture, or for both these purposes. The baffle member has the purpose of stabilizing the flame, The injection of the hydrocarbons at the center of the baffle member on the one hand prevents them from being supplied in the liquid state, which would necessitate their previous vaporization, and on the other hand retards their combustion and thus increases their cracking.

The invention has for its object to increase the quantity of carbon produced by cracking, which increases the luminosity of the flame and the quantity of carbon black which is produced.

It is a further object of the invention to increase the temperature up to which the hydrocarbons are brought.

A characteristic feature of the invention is that the cracking and burning device for hydrocarbons comprises an outlet surface for gas towards the periphery of the baffle member and means for supplying said surface with oxygen or oxygenated air. This placement of the outlet of the combustion-supporting gas rich in oxygen very effectively increases the effect on the hydrocarbons, of the increase in temperature of the flame produced by superoxygenation.

For a better understanding of the invention and to show the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which:

FIG. 1 is a longitudinal view, partly in section, of a device embodying the invention;

FIG. 2 is enlarged fragmentary view in section of an altemative form of part of the device shown in FIG. 1.

The burner of FIG. 1 comprises a premixing chamber 1 supplied with fuel gas through a pipe 2 and with combustion-supporting gas through a pipe 3. Along the axis of the chamber extend two concentric tubes 22 and 24. The tube 22 is supplied with secondary fuel through a pipe 4, while the space between these two tubes is supplied with combustion-supporting gas rich in oxygen, through a pipe 26. For example, natural gas passes in through the pipe 2, air through the pipe 3, natural gas or fuel oil through the pipe 4, and industrial oxygen or air enriched in oxygen through the pipe 26.

The tube 22 terminates in a thickened portion 28 forming a cone having an axial bare therethrough in which is disposed the end of the tube 22. The tube 24 terminates in a frustoconical flared portion 30, the base of which is in the same plane as that of the cone 28 and is located outside the chamber 1. Between the elements 28 and 30 is located an annular slot 32 through which passes out the combustion-supporting gas rich in oxygen.

FIG. 2 shows an alternative form of the nose of the burner.

The tube 22 is screwed into a nose 34 which constitutes the baffle member; a nozzle 36 is screwed into the extremity of the tube 22. The tube 24 is welded at the extremity of the nose directed towards the chamber 1; on the opposite side, the nose has a substantially flat surface 38. The oxygen or other combustion-supporting gas rich in oxygen, passing into the space between the tubes 22 and 24 expands into a chamber 40 which encloses the tube 22 and passes out through holes such as 42.

The axes of the holes 42 should not form too small an acute angle with the surface 38, in order to prevent the rich combustion-supporting gas which passes out from being mixed with the mixture which passes around the head. This axis forms for example an angle of 30 with the axis 44-46 of the head. The direction of the outlet of the rich combustion-supporting gas is the same as in the case shown in FIG. 1. By this means, the fraction of the mixture deflected by the baffle member returns the combustion-supporting gas towards the jet of hydrocarbons emerging from tube 22. It is probable that the rich combustion-supporting gas is only mixed, over a certain length of the flame, with the outer layer of the jet of hydrocarbons, producing at that point a high temperature, which causes the cracking of the hydrocarbons which are not mixed with combustion-supporting gas.

The oxygen introduced by the pipe 26, of the order of 4 percent of the total volume of oxygen utilized, makes it possible for example, to increase the temperature of the flame by 200 C. at cm. from the nose of the burner; in addition, the luminosity of the flame is substantially increased.

In the oxygen utilized, there must be included that which is supplied by the air circulating around the chamber 1. The device according to the invention may be mounted, for example, in the hearth of a furnace in which secondary air is intentionally introduced in order to complete the combustion.

The devices shown and described may be modified without thereby departing from the scope of the invention. For example, the outlet of the rich combustion-supporting gas may be closer to the outlet of the hydrocarbons. The latter may have very different volatilities, as for example propane and fuel oil.

A burner has been constructed with a nose as shown in FIG. 2, in which the internal diameter of the nozzle 36 was 30 mm. and the diameter of the face 38 was 159 mm. It comprised 48 holes 42 of 2 mm. in diameter, opening into the face 38 along a circle having a diameter of I32 mm. The face 38 projected from the extremity of the chamber 1 by about 15 centimeters.

To this burner, there were supplied:

through the pipe 2: 160 cu.m./hr. of Groningen gas;

through the pipe 3: 1,300 cu.m./hr. of air;

through the pipe 4: 490 cu.m./hr. of Groningen gas;

through the pipe 26: 40 cu.m./hr. of industrial oxygen of 99.5 percent purity.

As compared with a similar burner, but without the addition of oxygen, it was found that:

the white portion of the flame is slightly shorter, but much more luminous;

the content of carbon black is 3.5 times higher at 120 mm.

from the nose, and 1.9 times higher at 220 mm.

What we claim is:

1. Apparatus for cracking and burning hydrocarbons, comprising means defining a mixing chamber, means to supply fuel gas and a combustion-supporting gas to said chamber, said chamber having an outlet opening for the discharge of the mixed gases, a bafile member carried by the chamber in said opening and extending out of said chamber, a conduit passing through said baffle member and terminating in a central zone of the baffle member on the side of said baffle member opposite said chamber, means for supplying hydrocarbons to said conduit, and means to supply to the periphery of said baffle member air enriched in oxygen other than said combustion-supporting gas, said baffle member being in the form of a cone having its apex directed toward the mixing chamber, said supply means for air enriched in oxygen comprising means defining at least one passageway extending through said cone and terminating more closely adjacent said periphery of said baffle member than adjacent the axis of said cone.

2. Apparatus as claimed in claim 1, the terminal portion of said means defining at least one passageway being directed obliquely outwardly from the axis of said cone at substantially the angle of the generatrix of said cone.

conduit means surrounding said conduit and terminating in said annular chamber.

5. Apparatus as claimed in claim 1, said cone having a flat surface opposite said chamber disposed perpendicular to said conduit.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION 3,649,206 Dated March 1 1972 Patent No.

Inventor(s) Alix Ivernel It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, lines 26 and 27 should read prevents them, when they are being supplied in the liquid state, from being previously vaporized, and on the Signed and sealed this 7th day of November 1972 (SEAL) Attest:

EDWARD M,-FLETCHER,JR. ROBERT GO'I'TSCHALK Attesting Officer Commissioner of Patents JRM P0405) (1069) USCOMM-DC 6OS76-P69 UISI GOVERNMENT PR'NTING OFFICE: I969 0-355-33l. 

2. Apparatus as claimed in claim 1, the terminal portion of said means defining at least one passageway being directed obliquely outwardly from the axis of said cone at substantially the angle of the generatrix of said cone.
 3. Apparatus as claimed in claim 2, said means defining at least one passageway defining an annular conical passageway in said cone, and conduit means surrounding said conduit and terminating in said conical passageway.
 4. Apparatus as claimed in claim 2, said means defining at least one passageway defining a plurality of passageways communicating with an annular chamber within said cone, and conduit means surrounding said conduit and terminating in said annular chamber.
 5. Apparatus as claimed in claim 1, said cone having a flat surface opposite said chamber disposed perpendicular to said conduit. 